A typical digital subscriber line (DSL) communication network consists of a local unit and remote units, connected together by DSL. Each of the local and remote units can be equipped with various application interfaces such as G.703, Ethernet, and Nx64k. The application interface formats are transported between units over DSL pairs, such as over G.SHDSL (G.991.2) interfaces. In this manner a user is able to connect interfaces of the same type on different units. For example, a G.703 interface on a local unit may be connected to a G.703 interface on a remote unit.